Hi, I found the following guideline in World Machine 2 User Guide page 33 in regard to Polygon and Line type:

"Vertex-based shapes support bezier splines for smoothly interpolating between each vertex. This isslower to process but is often highly desireable to create smooth and complex geometry."

I took it that it means I can adjust the vertices of both Polygon Shape as well as the Line Shape. And indeed I can. In Line Shape, I can adjust the height of each vertex by right clicking the vertex, and select "Enter Precise Value". This allows me to not just adjust the Line shape in top-down 2-dimension, but also height in 3-dimension, creating a sloping Line shape.

Currently, I am not able to do so with Polygon shape. WM allows me to turn the shape into bezier shape and adjust each vertex just like Line Shape. It also allows me to "Enter Precise Value" for each vertex. However, entering those values has no effect on the vertex height of the Polygon shape. For example, imagine if we make a Polygon shape of a triangle at the value(height) of 512m. Then select one of the vertices and "Enter Precise Value" a value of 300m. You would expect the Polygon triangle to slope downward from 512m to 300m at that vertex. Instead, the Polygon triangle shape will remain flat at 512m.